I regularly switch between the NVIDIA GeForce 9400M ("Better battery life") and the NVIDIA GeForce 9600M GT ("Better graphics performance") on my mid-2009 MBP running OS X 10.6.3. I grew tired of clicking on the Energy Saver Preferences, and occasionally I would forget which GPU I was running until I opened the Preferences panel. After an unsuccessful search for a solution similar to the gfxCardStatus solution (gfxCardStatus: menu bar gpu status monitor for os x / cody krieger - mobile, desktop & web developer) for the new 2010 dual-GPU MBP line, I came up with my own GPU-for-dummies approach using Automator.

My solution uses two Automator apps to switch to the desired GPU. The apps (named "GPU-9400" and "GPU-9600") are in my Applications folder so I can access them easily. In addition to choosing the appropriate GPU with a simple click, the app also renames itself on the fly. This way, when I log back in after a GPU switch, I have a visual indication which GPU is currently in use. For example, when I click on the "GPU-9600" app, Automator will rename it to "GPU-9600 *ACTIVE*". If I then later click on "GPU-9400", Automator will rename it "GPU-9400 *ACTIVE*" and will also strip the "*ACTIVE*" from the GPU-9600 app name. There's a partial screenshot of my Applications menu at http://i249.photobucket.com/albums/g...PUSwitcher.jpg that explains it better than I can.

If you'd like to give it a try, here's what you need to do:
1. Download the ZIP file from shortcut to switch to 9600M graphics card? - Mac Forums, and unzip the two apps into your Applications folder. (I would have uploaded the file here but I'm a newbie here so I'm limited to 1MB files... D'oh!)
2. Assign the shortcut COMMAND-OPTION-S to System Preferences. (See Launch System Preferences with a keyboard shortcut | Software | Mac OS X Hints | Macworld if you need help doing this.)
IMPORTANT NOTE: You must use COMMAND-OPTION-S as the shortcut for these apps to function correctly.
3. Close all open applications (since switching your GPU is going to require a logout).
4. If you're currently running the NVIDIA GeForce 9400M (i.e. "Better battery life"), click on the "GPU-9600" app. Conversely, if you're currently running the NVIDIA GeForce 9600M GT (i.e. "Better graphics performance"), click on the "GPU-9400" app.
IMPORTANT NOTE: If you click on the app that corresponds to the GPU you're already running, the app will successfully rename itself to indicate the GPU is active, but the app will then error out since it's expecting a logout prompt which obviously won't appear.

I built this for my personal use, so I have only used this on my mid-2009 MBP running OS X 10.6.3. Depending on your hardware and OS version, your mileage may vary. As with all applications, I *STRONGLY* recommend you backup your system before running these apps. The Automator scripts in the apps are simple and won't cause any damage to your system or files if they fail, but safe is always better than sorry. There is no warranty on these apps and they are provided "as-is".

Also, because these are simple Automator apps, you can edit them in Automator if you'd like to tweak the behavior to your needs.